Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!wuarchive!cs.utexas.edu!milano!cadillac!harp
From: harp@cadillac.Berkeley.EDU (Christopher North-Keys)
Newsgroups: comp.windows.x
Subject: Re:  Wish list for R5
Message-ID: <10370@cadillac.CAD.MCC.COM>
Date: 13 Aug 90 09:32:50 GMT
References: <9008130225.AA21698@shamash.McRCIM.McGill.EDU>
Sender: news@cadillac.CAD.MCC.COM
Reply-To: harp@cadillac.Berkeley.EDU (Christopher North-Keys)
Lines: 64


This is a minor detail (ah, well) relating to the X authority interface.

According to my interpretation of the man page, and the evidence presented
by direct experimentation, there is a basic tool missing from the xauth
program.

Group Talisman had little difficulty working out the usage of the
MIT-MAGIC-COOKIE-1 mechanism, and indeed are using it now between the 
Uni.Tx@Austin, MCC, and MIT.  However, in order to avoid using
script ftp sessions between MCC(secured vs. rsh and rlogin) and MIT, it became
necessary to add new cookies *ONLY* in the event they did not already
exist.  This usage of fixed cookies (now that sounds strange...) seemed
like an obvious thing to do, but it's here that the problems arose.

I already knew there was a simple operation to override existing entries,
now what I needed was either a command which only overrode *missing* entries,
or a way to test for the existance of an entry.

The first didn't exists.  Oh, well, I figured, "sure", the second would be
there.  No need to run ``grep $DISPLAY $XAUTHORITY'' (Nasty! Yechh! Bad!)
or anything like that.  Surely...

Bad news.   ``xauth list $DISPLAY'' returns success even if the display in
question has no existing cookie.

Now I'm using (C-Shell):

    set xkey = 2004`date +%j%m%d%y%H%M%S`0feedface
    xauth add unix:0.0 . $xkey
    if ( 0 == `xauth list $DISPLAY | wc -l` ) xauth add $DISPLAY . $xkey

This is *ugly*.  I figured the third line *should* be something like:

    xauth list $DISPLAY || xauth add $DISPLAY . $xkey

or even better (add-if-missing):

    xauth verify $DISPLAY . $xkey

Which would allow:

    set xkey = 2004`date +%j%m%d%y%H%M%S`0feedface
    cat <<... | xauth >>& /dev/null
        add unix:0.0 . $xkey
        verify $DISPLAY . $xkey
    ...

But both if these approaches drew double-nulls.

Now, if the idea it that the cookies should *always* be dynamic, it's already
suffering, because there's no decent way to reload cookies during a session
with xrdb or the like just now...but if it was expected they might be static:

  Could someone please fix it?  Please?  We *have* to use it, but fixing it
  ourselves it rather hard in places where the words ``in my copious spare
  time'' have become a running joke...

Of course, if we just missed something: yell at us (rather, me), eh?

______________________________________________________________________________
Christopher North-Keys                                  Assoc. Systems Analyst
Group Talisman                                                  Harp[@Mcc.Com]
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